This invention relates to portable door securing devices which may be temporarily installed on the inside of an inwardly swinging entrance door preventing unauthorized entry into the room or building. More particularly, the invention relates to an improved portable door lock the type wherein the lock is installed to extend between the door and associated frame with the first portion of the lock being engaged with the frame mounted strike plate and a second portion of the lock being moved into abutment and secured against the surface of the door preventing inward movement thereof, which can be attached and removed in one step.
The need for and desirability of portable door locks being utilized by occupants of a building or room for securing the entrance has long been recognized. Such locks are for example advantageous as a supplemental lock for hotel or motel rooms since the occupants of these premises have no control over access to keys and/or security chains can be easily broken. Further, although various permanently mounted auxiliary locks are sometimes provided, such devices do not necessarily provide the desired degree of protection and are not always maintained in a proper operating condition and statistics indicate that past employees are often involved in motel/hotel break-ins.
A variety of supplemental locking devices that are easily stored and/or carried in a suitcase, purse or other container have been taught in the prior art. Such prior art devices include auxiliary locking arrangements which include a relatively thin locking bar or extension to be placed between the door and the frame and interact with the strike plate preventing movement of the bar in the direction of the door opening. A blocking member is then generally moved along or interacts with the locking bar and is secured in abutment with the inner surface of the door.
Prior art devices which deal with the above noted problem include U.S. Pat. No. 633,078 granted to Crane on Sept. 12, 1899 and discloses a locking bar for placement between the door and the frame interacting with the strike plate, and a transversely positionable wedge member which is then secured against the door and frame preventing relative movement therebetween.
U.S. Pat. No. 1,544,480 granted to Racine on June 30, 1925 discloses a locking bar for interaction with the strike plate and a sliding ratchet type device used in conjunction with an inclined plane to secure a device against the door preventing inward movement thereof.
U.S. Pat. No. 2,969,253 granted to Schettel on June 24, 1961 discloses a blade for interacting with the strike plate and a piece of resilient material which is forced into abutment against the door and secured to place by a device which in normal position prevents inward movement of the door by interacting with saw teeth on the blade but is quickly released by moving the securement device out of alignment.
U.S. Pat. No. 3,416,333 granted to Weingart Dec. 17, 1968 discloses a travel lock having a blade to interact with the strike plate having opposing serrated edges which interact with a second plate abutting the door and the frame at right angles to the blade.
U.S. Pat. No. 3,429,151 granted to Weingart Feb. 25, 1969 discloses essentially an identical device to the lock patent granted in '68 however it includes a threaded member to interact with the blade allowing more precise adjustment.
U.S. Pat. No. 3,423,968 granted to Foote Jan. 28, 1969 discloses a blade having opposing serrated edges and a key lock device for interacting with those edges preventing movement of the door.
U.S. Pat. No. 3,451,235 granted to Weingart on June 24, 1969 discloses yet another variation of a door lock whereas opposed to edge serrations he includes notches at approximately the center of the blade interacting with a perpendicular slide plate.
U.S. Pat. No. 3,476,929 granted Nov. 4, 1969 to Weingart discloses a locking device similar to that of the '235 patent only adapted for use on drawers as well as doors.
U.S. Pat. No. 3,596,961 granted to Lippman Aug. 3, 1971 discloses a door locking device including a blade for interacting with the strike plate and including opposing serrated edges interacting with a spring biased abutment plate which latches on the serrations.
U.S. Pat. No. 4,285,535 granted to Leary on Aug. 25, 1981 discloses a blade for interacting with the latch plate and a door abutting device which is secured in position by the interaction of a threaded rod extending from the blade interacting with a latch mechanism and congruent threads for adjusting the door abutting means.